It is known that when a coating solution containing a dichroic liquid crystal compound having lyotropic liquid crystallinity is applied to a substrate surface, which has been subjected to an alignment treatment, and the coating film is cured, a polarizer layer having an absorption axis in a predetermined direction is obtained (Patent Document 1). The principle on which the polarizer layer has an absorption axis in a predetermined direction lies in that the dichroic liquid crystal compound is aligned in a predetermined direction in accordance with the substrate surface subjected to an alignment treatment.
By applying the above-mentioned principle, a substrate, the surface of which is divided into a plurality of regions, and each of which is subjected to a different alignment treatment, can be used as the aforementioned substrate, and a patterning polarizer layer having a plurality of polarization regions which differ in the direction of the absorption axis can be formed (Patent Documents 2 and 3).
Since the patterning polarizer layer has a plurality of polarizing regions different in the direction of the absorption axis as described above, transmission or non-transmission of light can be controlled in accordance with the directions of absorption axes of those polarizing regions. That is, when specific linearly polarized light is thrown on the patterning polarizer layer, the polarized light is transmitted at some polarizing regions, and the polarized light is not transmitted at other polarizing regions.
An optical laminated body having the above-mentioned patterning polarizer layer can be used for a genuineness determination medium utilizing a latent image, or the like.
In conventional patterning polarizer layers, however, only transmission or non-transmission of polarized light in a plurality of polarizing regions can be controlled. Therefore, when the conventional patterning polarizer layer is used for, for example, a genuineness determination medium, it is difficult to set in the polarizer layer a latent image having a more complicated pattern.    [Patent Document 1]
Japanese Unexamined Patent Publication No. 2009-173849    [Patent Document 2]
Japanese Patent No. 4168173 (Japanese Unexamined Patent Publication No. 2001-159713)    [Patent Document 3]
Japanese Patent No. 4175455 (Japanese Unexamined Patent Publication No. 2002-357720)
An object of the present invention is to provide an optical laminated body having a patterning polarizer layer in which a more complicated pattern can be set, and a method for production of the optical laminated body.
The optical laminated body of the present invention has a patterning polarizer layer having at least two polarizing regions having different single transmittances, and a substrate.
In a preferable optical laminated body of the present invention, the patterning polarizer layer is formed by applying to the surface of the substrate a coating solution containing a dichroic liquid crystal compound using a printing method.
In a further preferable optical laminated body of the present invention, the optical laminated body has a part in which the two polarizing regions are different in thickness.
In a further preferable optical laminated body of the present invention, the patterning polarizer layer contains an aligned dichroic liquid crystal compound.
In a further preferable optical laminated body of the present invention, the dichroic liquid crystal compound has lyotropic liquid crystallinity.
In another aspect of the present invention, a method for production of an optical laminated body is provided.
In this method for production of an optical laminated body, a coating solution containing a dichroic liquid crystal compound is applied to the surface of a substrate using a printing machine to form a patterning polarizer layer on the surface of the substrate.
In a preferable method for production of an optical laminated body, the patterning polarizer layer is formed by applying a coating solution to the substrate while changing the application amount of the coating solution.
In a further preferable method for production of an optical laminated body, the surface of the substrate is subjected to an alignment treatment.
The optical laminated body of the present invention has a patterning polarizer layer having at least two polarizing regions having different single transmittances, and therefore a more complicated pattern can be set.